Epigenetic Markers to Predict Conversion From Gestational Diabetes to Type 2 Diabetes.

Abstract

Lifestyle factors mediate epigenetic changes that can cause chronic diseases. Although animal and laboratory studies link epigenetic changes to diabetes, epigenetic information in women with gestational diabetes (GDM) and type 2 diabetes is lacking. This study sought to measure epigenetic markers across pregnancy and early postpartum and identify markers that could be used as predictors for conversion from GDM to type 2 diabetes. Global histone H3 dimethylation was measured in white blood cells at three time points: 30 wk gestation, 8-10 wk postpartum, and 20 wk postpartum, from four groups of women with and without diabetes. A total of 39 participants (six to nine in each group) were recruited including: nondiabetic women; women with GDM who developed postpartum type 2 diabetes; women with GDM without postpartum type 2 diabetes; and women with type 2 diabetes. Percentages of dimethylation of H3 histones relative to total H3 histone methylation were compared between diabetic/nondiabetic groups using appropriate comparative statistics. H3K27 dimethylation was 50-60% lower at 8-10 and 20 wk postpartum in women with GDM who developed type 2 diabetes, compared with nondiabetic women. H3K4 dimethylation was 75% lower at 8-10 wk postpartum in women with GDM who subsequently developed type 2 diabetes compared with women who had GDM who did not. The percentage of dimethylation of histones H3K27 and H3K4 varied with diabetic state and has the potential as a predictive tool to identify women who will convert from GDM to type 2 diabetes.